The present invention relates to a system for the transport, storage, mixing and resuspension of sterile and non-sterile liquids. In particular, it relates to a system for use with suspensions used in the pharmaceutical industry.
In the chemical industry, and in particular the pharmaceutical industry, there is a need for a system capable of holding liquids and mixtures of liquids and solids where a sterile environment can be maintained while providing means for stirring, mixing, resuspending, sampling and complete delivery of the contents. To date, the industry has relied upon stainless steel storage vessels with associated stirring devices, ports and mixers. These associated pieces of equipment require special seals in order to assure that the sterile conditions established within the device are maintained during mixing and pumping.
Due to the weight of these stainless steel devices, they are difficult to maneuver, which leads to increased production times. These stainless steel systems often require special handling equipment. When these stainless steel devices are used to transport bulk product, significantly higher shipping costs result due to the weight of the container and the added cost of returning the empty system for future use.
Since the stainless steel systems are not disposable, they must be cleaned and resterilized before being reused. This may involve chemical cleaning with agents such as perchlorate solution, and the attendant disposal problems associated with disposal of such products. After cleaning, the systems must be inspected and tested to assure that all foreign matter has been removed. Since new products will be introduced, validation of the cleaning and resterilization procedures as well as tests to assure efficacy must be completed. This also adds to the costs and complication of using the stainless steel systems.
Since the stainless steel systems are expensive, it is not cost effective to maintain several different sizes of the vessels. As a result, vessel size is usually set to the largest expected batch of material. When small batches are prepared, they are stored in oversized containers with the attendant costs and problems which have been previously described.
One of the primary uses for this type of vessel is the storage and transportation of sterile suspensions of alum in an aqueous medium for use in the production of vaccines. In practice, a sterile alum suspension is prepared in the vessel and shipped to the area where inoculation with the bulk virus or bacteria stock will occur. Since the suspension may be prepared well in advance of inoculation, the system must also serve as a storage container.
Prior to inoculation, the alum must often be resuspended. In many instances, uniform particle size and the preparation of a homogeneous suspension of the alum are critical to the success of the final product. Once resuspension has been assured, the suspension may be pumped into a vessel where inoculation will occur or inoculation may be carried out in the storage container.
It is apparent that certain production, shipping and storage problems exist with the current systems.
It is therefore the object of this invention to replace the stainless steel container with a plastic system which is lighter, less expensive, disposable, affords a procedure to resuspend any materials that may settle over time, maintains sterility, and provides a means of obtaining samples of the contents so that uniformity can be assured.
It is a further object to provide a system that can be used where a sterile environment is not necessary.
In order to provide such a system the device must be capable of assuming any needed volume. It must also be capable of being sterilized and maintaining the sterile environment for extended periods of time. Additionally, the surface of the device which comes in contact with the vaccine suspension must not interact with the product. That is, it must not absorb protein, adjuvants or other ingredients from the suspension. Additionally, all fittings and connections to the device must be sterilizable and must be capable of maintaining the sterility of the product during storage.
In order to be practical in an environment including sterile vaccines, the new system must be capable of resuspending alum within a two hour period of time. More conveniently, the resuspension should be possible within 30 minutes.
The product must also be capable of being shipped by regular carrier over great distances or moved by conventional carts inside a manufacturing area.
Since the uniformity of the suspension is critical to the uniformity of the final vaccine product, the device must allow dispensing of product with no apparent settling during the dispensing period. In addition, the system must be designed to deliver as much of the suspension as possible so that only a minimal amount of material is retained within the system once dispensing is complete.
The device of this invention provides for a light weight, sterilizable system capable of mixing, storing, resuspending, shipping and dispensing solutions or suspensions. The instant device of this invention has demonstrated the ability to overcome the problems discussed above and provide reliable, homogeneous suspensions for the manufacture, mixing, storage and dispensing of aqueous suspensions.